GC suddenly halves size of Old space causing major GC thrashing

A large, stable application suddenly started to exhibit strange GC behavior: the size of the Old generation started to slowly decrease. Now, after 11 days, the size of the Old generation is roughly 1/2 what it has been for three years. As a result we are enduring major GCs continually.
Specifics:
JDK 1.5.05_05, running on 16cpu SunFire V890 with 16GB RAM.
-server -Xmx10g -Xms10g -XX:NewSize=1g -XX:MaxNewSize=1g -XX:MaxGCPauseMillis=5000 -XX:GCTimeRatio=19
In short, we have a fixed New space size of 1G, and a roughly 9G Old space.
As you can see, we are not allowing adapative resizing. A "jstat -gccapacity" log shows that the minimum and maximum Old size (OGCMN and OGCMX) are 9G (which is what we expect and have always seen), but the current Old size (OGC) is now down to 4.6G, and is at 99.96% capacity. OGC has been at 9G for years until 11 days ago, when it started to steadily drop.
With both jconsole and jstat we can see the New space happily bouncing between 0 and 1.0G in size, with lots of minor GCs (sub-second in duration). The Full GCs seemily occur at any point in the New space's capacity (i.e., they do not always occur when New is full).
Another odd observation: the major GC's are occuring nearly every 10 minutes, +/30 seconds of variation. There are no external GC invocations occuring. The app does not have RMI and is not a database client. No soft/weak references are in use. No software change was made prior to the start of the shrinking-old-space behavior.
This is a typical high-capacity on-line application servicing about 300,000 transactions daily, and creates billions of objects in doing so, in which the Old space is storing customer information and transactions; in other words a steadily growing body of long-lived objects and a ferocious number of very short-term objects. It is rare (prior to this) to see major GCs. Daily maintenance is performed to cull objects (e.g., old transactions) out of the Old space, and a nightly major GC is invoked in order to avoid major GCs during our busy business hours.
It looks to us like the JVM/GC has suddenly decided to start resizing downward our Old space and is ignoring nearly 5GB of available space. We have detailed jstat logs available.

The drop in the old generation size is a combination of a bug
(6524727) and the 5 second pause time goal you used.
That bug talks about the young generation minimum size not being
honored but may also allow the old generation to shrink so that the overall
heap falls below the -Xms minimum.
The GC ergonomics is trying to get to the 5 second goal by
reducing the size of the old generation. I think in this case it
is just not achievable. In the jstat logs I saw full collections taking
in the 10's of seconds. The workaround is to turn off GC
ergonomics with -XX:-UseAdaptiveSizePolicy.

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Usage of Effective Old Space

Hello everybody
In a EWA of one of our ABAP+JAVA system we get this alert:
Usage of Effective Old Space
The resource utilization is critical and leaves no room to cope with sudden high-load situations.
The higher the value, the harder it is to cope with high load situations. If more than 80% of old space is used, high-load situations can lead to rapid growth phases within the old space and therefore to sudden resource outages. As a result, average values that are higher than 80% can indicate critical resource utilization.
Recommendation:
If persistently high values of effective old-space usage are observed, related parameters (such as the old-space growth rate) should be analyzed as a preliminary measure. If growth rates are observed within the cluster-high old space, this may be due to high baseline resource utilization.
In some cases, adding additional server nodes to use the available resources more efficiently may be recommended in order to reduce the overall baseline usage. It may be advisable to enlarge the heap, depending on the type of application deployed and the operating system used. However, an increased heap size will also increase the average time required for a full garbage collection, and so any changes will have to be analyzed carefully using the parameters defined here.
Any help will be apperciate.
Best regards
Rubé

Hi,
This suggest that your tenured memory is set to low. Could be that the application footprint is growing e.g. due to more users working on the system or heavier usage per user. High effective old space usage could lead to more frequent garbage collection or out of memory dumps. You could try to increase the max heap size (-Xmx), but this could also lead to longer garbage collection times. You could also try to create another server node, to load balance the work (and application footprint).
Afterwards check with Wily Introscope the effective old space usage.
Regards,
Bart.

I was backing up my iPhone and importing photos onto iPhoto at the same time , then suddenly it says no more space available (i had 48GB before i do this and now i have 18GB) i can't find the back up or the photo anywhere , how can i delete them ?

i was backing up my iPhone and importing photos onto iPhoto at the same time , then suddenly it says no more space available (i had 48GB before i do this and now i have 18GB) i can't find the back up or the photo anywhere , how can i delete them ? i dont need the pictures or the back ups , i want to delete them but they are not there

Empty the Trash if you haven't already done so. If you use iPhoto, empty its internal Trash first:
iPhoto ▹ Empty Trash
Do the same in other applications, such as Aperture, that have an internal Trash feature. Then reboot. That will temporarily free up some space.
According to Apple documentation, you need at least 9 GB of available space on the startup volume (as shown in the Finder Info window) for normal operation. You also need enough space left over to allow for growth of the data. There is little or no performance advantage to having more available space than the minimum Apple recommends. Available storage space that you'll never use is wasted space.
When Time Machine backs up a portable Mac, some of the free space will be used to make local snapshots, which are backup copies of recently deleted files. The space occupied by local snapshots is reported as available by the Finder, and should be considered as such. In the Storage display of System Information, local snapshots are shown asBackups. The snapshots are automatically deleted when they expire or when free space falls below a certain level. You ordinarily don't need to, and should not, delete local snapshots yourself. If you followed bad advice to disable local snapshots by running a shell command, you may have ended up with a lot of data in the Other category. Reboot and it should go away.
See this support article for some simple ways to free up storage space.
You can more effectively use a tool such as OmniDiskSweeper (ODS) to explore the volume and find out what's taking up the space. You can also delete files with it, but don't do that unless you're sure that you know what you're deleting and that all data is safely backed up. That means you have multiple backups, not just one.
Deleting files inside an iPhoto or Aperture library will corrupt the library. Any changes to a photo library must be made from within the application that created it. The same goes for Mail files.
Proceed further only if the problem isn't solved by the above steps.
ODS can't see the whole filesystem when you run it just by double-clicking; it only sees files that you have permission to read. To see everything, you have to run it as root.
Back up all data now.
If you have more than one user account, make sure you're logged in as an administrator. The administrator account is the one that was created automatically when you first set up the computer.
Install ODS in the Applications folder as usual. Quit it if it's running.
Triple-click anywhere in the line of text below on this page to select it, then copy the selected text to the Clipboard by pressing the key combination command-C:
sudo /Applications/OmniDiskSweeper.app/Contents/MacOS/OmniDiskSweeper
Launch the built-in Terminal application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Terminal in the icon grid.
Paste into the Terminal window (command-V). You'll be prompted for your login password, which won't be displayed when you type it. You may get a one-time warning to be careful. If you see a message that your username "is not in the sudoers file," then you're not logged in as an administrator.
The application window will open, eventually showing all files in all folders, sorted by size with the largest at the top. It may take a few minutes for ODS to finish scanning.
I don't recommend that you make a habit of doing this. Don't delete anything while running ODS as root. If something needs to be deleted, make sure you know what it is and how it got there, and then delete it by other, safer, means. When in doubt, leave it alone or ask for guidance.
When you're done with ODS, quit it and also quit Terminal.

Could Very Low Disk Space Cause problems?

Hi, my 600 GB Hard Drive only had around 5 GB of space left . I purchased a new 1 TB Hard Drive in order to delete media so that I could gain the space back. I've since gained back 200 GB of Space but Could very low disk space cause issues? What kind of issues could occur? Thanks
Message was edited by: Stuart Lawrence

There are any number of reasons for occasional beachballs to appear. They will appear when some programs are involved in heavy disk I/O which tends to be processor dependent and causes the program to suspend all other activity until the disk activity has completed. This is more often the case when writing to the disk. Beachballs may also appear if the OS has to use disk I/O and is slowed down by an over-filled and/or fragmented hard drive. The fuller a drive gets the greater the likelihood that fragmentation will become a more noticeable problem. Beachballs can appear if you are low on physical memory so applications must resort to disk-based virtual memory which is considerably slower and tends to cause the computer to become slow or unresponsive for a period of time. It can also cause disk-thrashing. Beachballs can occur if the disk has become corrupted causing applications to have difficulty reading from or writing to the disk.
It is possible to repair a drive's directory, and it's even possible to identify corrupted files, but it's not possible to repair corrupted files nor repair a corrupted drive. If a drive develops corrupted files either the files will need to be replaced or deleted. If a drive develops soft sector errors these can be repaired by erasing the drive (reformatting.) If a drive develops hard sector errors these may or may not be repairable, but if they are repairable it requires zeroing the data during a disk formatting operation. If the disk directory becomes corrupted that can be repaired using Disk Utility or one of the various third-party utilities such as Disk Warrior. Disk Utility can repair many but not all directory corruption problems. What DU cannot fix Disk Warrior usually can.
You can start repairing a drive as follows;
Repairing the Hard Drive and Permissions
Boot from your OS X Installer disc. After the installer loads select your language and click on the Continue button. When the menu bar appears select Disk Utility from the Installer menu (Utilities menu for Tiger and Leopard.) After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list. In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive. If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit DU and return to the installer. Now restart normally.
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Old Space Utilization

Hello there! Using jstat with -gc flag to analyze our server's health indicates that we are using aroung 1GB of Old Space. But after dumping the heap using jmap. And using a tool (Eclipse Memory Analyzer Tool and Yourkit) both indicates that the heap has only 223mb.
Is this a normal behaviour?
Regards

When you say "using around 1Gb of Old Space", what do you mean? The size of the space is 1Gb or the amount of the data in it is 1Gb?
I recommend jvisualvm with the Visual GC plugin installed for analysing heap space.

I just had to reformat the external hard drive that houses my iPhoto library, then restore it from a backup. Now Time Machine is telling me my backup hard drive suddenly does not have the space to complete a backup. I also noticed when I go in to Time Mac

I just had to reformat the external hard drive that houses my iPhoto library, then restore it from a backup. Now Time Machine is telling me my backup hard drive suddenly does not have the space to complete a backup. I also noticed when I go in to Time Machine, there are only about 5 backups recorded on the ext. hard drive. There were many more before. Any idea what happened and if I have to buy a new back up hard drive?

Hallo Kieth ,
I am not quite ready to restore the full iphoto library , as I have days of work re - imputting titles,descriptions and enhancement . I hope that your suggestion works , as I use my Macbook basically to work with digital photography. Through time , I will need to delete my library to recover more disc space and I would hate to have to spend more time re - imputting titles and descriptions all over again .
Thanks for your interest and advice.
regards - Alan

Spaces causing system freeze and logout

Recently (probably within the last 2-3 weeks) I've been having some issues with switching between spaces. It doesn't happen every time, but occasionally when I switch to another space my entire computer will freeze in the middle of the animation. After a few seconds, my screen will go blue and I'll get logged out.
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I have a similar problem with Spaces under OS X 10.6.4 on my MacBookPro5,3.
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-kb

How can validate the ASM size and free space correctly?

Dears ,,
I faced problem in ASM size as it appeared in alert file as below
ORA-19504: failed to create file "+DG_DATA"
ORA-17502: ksfdcre:4 Failed to create file +DG_DATA
ORA-15041: diskgroup space exhausted
So we resize ASM space and large it. But we faced the same problem also although there is free space in ASM.
It seems that the shown free space is not real.
How can validate the ASM size and free space correctly?
Thanks & Regards,,

*Oracle DBA* wrote:
Dears ,,
I faced problem in ASM size as it appeared in alert file as below
ORA-19504: failed to create file "+DG_DATA"
ORA-17502: ksfdcre:4 Failed to create file +DG_DATA
ORA-15041: diskgroup space exhausted
So we resize ASM space and large it. But we faced the same problem also although there is free space in ASM.
It seems that the shown free space is not real.
How can validate the ASM size and free space correctly?
Thanks & Regards,,
I was having this problem. Im my case i couldn add datafiles to a tablespace despite the fact that i was having a lot of space in the asm. Try rebalancing. It might help. In my case rebalancing also didn work because it seems that there need to be a threshold space in all the disks for the rebalancing to happen which was not in my case, so i had to shrink some unused space in the tablespace and then after gaining the required space I rebalanced the disk and then the disks got rebalanced, also i was able to use the free space that was showing .

How to reduce size of AW Space?

Hi,
I want to reduce size of AW Space. It means size of BLOB in tablespace.
1) My AW Space have 60 GB
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Thanks Vasek.

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AW attach rwx
make a trivial change such as make a change to a scalar variable youâve created
e.g.
define my_var variable int
my_var = 1
Update
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my_var=2
Update
commit;
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Removing Blank Spaces caused by Supressed data

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When i switch to iCloud does all the music on my phone suddenly not take up any space?

when i switch to iCloud does all the music on my phone suddenly not take up any space?

This is how it was advertised but it is not exactly true unless all your music was bought in iTunes. You can always redownload a song that was previously bought for free.
Eventually for a fee they will offer iTunes match and you will be able to do that for other music too that you have ripped off of CDs, for exmple.
If you have more than one Apple ID, though, like so many of us that came from Mobile me, this service will not really work because you can only flip between one ID and another on an IOS device once every 90 days. We are not allowed to merge our IDs, so iCloud does not really work for us.

List size of table spaces

Hello,
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SQL> select u.tblspc "TBLSPC", a.fbytes "ALLOC", u.ebytes USED, a.fbytes-u.ebytes UNUSED,
2 (u.ebytes/a.fbytes)*100 USEDPCT
3 from (select tablespace_name tblspc, sum(bytes) ebytes
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6 (select tablespace_name tblspc, sum(bytes) fbytes
7 from sys.dba_data_files
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CARTEST_IDX 83886080 46465024 37421056 55,390625
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By adding an external hd to time capsule does it increase the size of available space for time machine back-ups?

By adding an external hd to time capsule does it increase the size of available space for time machine back-ups?

No, each drive is treated separately. Sorry!!

A seeming small change by Verizon causes major monetary and unrecoverable damages

A seeming small change by Verizon causes major monetary and unrecoverable damages
Back, I think in March or so, Verizon changed how they bill. Prior to this time frame my elderly mom paid the phone bill and I paid the DSL bill. The DSL bill came on my name and I paid by credit card and the phone bill came under her name and she paid by direct debit. She will not use a computer.
So, they make both bills on her name and won't change it. They did, however, allow the payment from my credit card.
The first unfortunate consequence was the internet speed suddenly dropped in speed by a factor of 2 to 1.5/364 and it did take me probably a month to notice it. NO ONE that I called was able to find the problem. It took multiple attempts until some bright “call in technician” said the problem is on their end and could be fixed in software. Thus, I believe, because of the name change, the provision changed too. The phone line crapped out too at this time.
The troubleshooting was stupid too. I took another modem and connected it directly to the NID and directly to the laptop and the technician on the phone said, it's either in your house or your modem and wanted to send me a new modem which they did. I don' get it. This is the wrong conclusion.
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Verizon sent me a D-link model DSL-2750B modem which I have to return because its just plain old stupid. It boasts Wireless n and the wired ports are 10/100. What's up with that? Next, there are no line stats and a horrible interface, akin to Verizon's website. Still can't figure out how to put it in Bridge mode. I own a D-link repeater and the interface is fine.
I asked them what modem they would send me and they would not tell me, so I got whatever piece of junk they had lying around.
I have now purchased a Network RAID array with no wireless access and with ~400 mb/s access rates. Yep, really stupid router.
Because of the number of outages, I have to be able to quickly switch from a bridge connected modem, Westel 6100) to one that is connected in direct mode, a Westell 2200 It's almost easy, but not quite, since the equipment is up in the rafters in the laundry room. The DSL cable is commercial terminated CAT5, which is rare. The modem is within 6' of the NID.
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I have already upgraded my network infrastructure to include a UPS for the network infrastructure and POE (Power over Ethernet) for the DSL modem. The UPS backup does not backup a repeater although it may in the future.
Now, let's go back to this seeming innocuous billing change.
So, this constant having to access the modem in the alternate configuration and a medical condition (migraines) that makes it hard to think clearly. So, in one of these episodes, I placed my laptop on top a container that was soaking laundry.
So, the LCD screen has to be replaced at $300 and the battery had to be replaced. Then the Ethernet cord to the modem got pulled and caused the laptop to fall on the floor. It worked for a few weeks and then suffered an UNRECOVERABE hard drive crash.
During this time frame, in fact over a 2 day period. My mom ended up in the hospital and to a rehab facility. My car ended up staying in the shop for a few days because of parts unavailability. My hard drive crashed and their was water in the basement. I don't have time for this.
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Plans are to contact the billing office and the attorney general's office in the state where billing questions need to be resolved.
The last outage, fixed on July 27, was flagged as a phone outage by Verizon, when 18 routers supposedly died. 18 routers suspiciously means that they they were not adequately protected against surges. Verizon should look at the way DelMarVa Power reports outages: see: Delmarva, Put the usual World Wide Web Prefix and the COMercial domain suffix
For god's sake, quit making the website circular. I though Yahoo was the expert in that. I never visit Verizon's website unless there are problems. I mistaking thought I could find outage information, say using my phone's browser. This time I had to purchase service from CLEAR internet to ride me through this fix.
I know, you can't fix stupid and you can always find a better idiot. Comcast is looking more attractive.
Compensation of or my loss I will probably never get, but maybe with the help of the attorney general I can get the billing fixed. I do have power of attorney. Now, of course, the name the Verizon Website addresses me as is not right on this forum.
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I am fortunate that my service with Verizon Fios has been very reliable and that I haven't had too many issues over the years. But don't get me started on Verizon Wireless. I am through with doing any more business with them once my cell phone minutes run out. I love it when they say they have done everything the could to investigate such a simple issue with running my debit card transaction wrong and blaming it on my bank, i.e. running it through as a "debit" when I choose "credit" all of a sudden now two times in a row after 4 years of doing it right as "credit". And now they consider the issue closed on their end when nothing has been resolved. That's no way to treat a long time customer and I really felt treated like I was a bother to them. It's not like I ever paid them much money for this pre-paid cell phone service that I have used infrequently but I was really mad at the way they just wrote this off and pretty much told me "too bad". Talk about "customer non-service". It's also very hard to track the number of minutes left on my balance. I'm due for an upgrade anyway. I want to switch to the I-Phone from this flip phone but never again with Verizon Wireless. T-Mobile is way more attractive. Verizon Wireless is not only an entity separatedfrom Fios but it's definitely a much different animal and their customer service has really gone downhill. When you're treated like they don't care, it's maddening.
My customer service experience with Fios overall has been far superior to that most of the time. My setup is simple and even though there are some people who will inevitably complain about anything just to vent, I definitely believe at least some of what is posted here. And switching TV, phone, and Internet providers is a lot more involved than switching a cell phone provider.

Downloaded Mountain Lion and it caused major problems

Down loaded Mountian Lion and caused major problems long story short had to reinstall Leopard then Lion but I lost my iTunes library. I thought if you had icloud you could recover you library. Or just log into iTunes and your library would appear. Appearantly not because I lost over 3k songs can someone help me with this if possible.

Reinstall from your most recent backup...
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GC suddenly halves size of Old space causing major GC thrashing

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